Turbine apparatus and governor for turbine

Abstract

In a turbine apparatus comprising a runner rotatable to be rotationally driven by a water, a gain of a derivative calculation element generating a derivative component of a control signal for controlling a flow rate of the water which derivative component is to be applied to the derivative calculation element and the integration calculation element by performing differentiation on a difference between an actual rotational speed and a desired rotational speed of the runner with respect to a time proceeding has a value sufficiently increased to converge a value of the control signal toward a desired value in accordance with the time proceeding in S-characteristic portion.

1. A method for operating a pump turbine apparatus including a runner rotatable in either of a direction for driving an electric power generator and a direction for pumping a water, a main shaft for transmitting a rotation of the runner to the electric power generator, a wicket gate for adjusting a flow rate of water for driving the runner, and a governor for controlling an opening area of the wicket gate to change a rotational speed of the runner,
 wherein when the rotational speed of the runner is adjusted to be synchronized with a frequency of an electric power transmission line during rotational start of the runner in an electric power generating mode and a head of the water is not more than a predetermined value, a derivative calculation element is dominant in comparison with the other calculation element to mainly control the rotational speed of the runner in a rotational speed control system. 
 
     
     
       2. A method according to  claim 1 , wherein a dominance of the derivative calculation element when the rotational speed of the runner is adjusted to be synchronized with the frequency of the electric power transmission line during rotational start of the runner in the electric power generating mode and the head of the water is not more than the predetermined value is significantly higher than the dominance of the derivative calculation element during a regular operation of the pump turbine apparatus. 
     
     
       3. A method according to  claim 1 , wherein a dominance of the derivative calculation element when the rotational speed of the runner is adjusted to be synchronized with the frequency of the electric power transmission line during rotational start of the runner in the electric power generating mode and the head of the water is not more than the predetermined value is significantly higher than the dominance of the derivative calculation element before the rotational speed of the runner is adjusted to be synchronized with the frequency of the electric power transmission line. 
     
     
       4. A method according to  claim 1 , wherein when the rotational speed of the runner is adjusted to be synchronized with the frequency of the electric power transmission line, the rotational speed of the runner is adjusted in the vicinity of a rated rotational speed thereof to be synchronized with the frequency of the electric power transmission line, a gain Ki of an integration calculation element along IEC International Standard 61362 First Edition is significantly decreased in comparison with the gain Ki before the rotational speed of the runner is adjusted to be synchronized with the frequency of the electric power transmission line, and a gain Kd of the derivative calculation element along IEC International Standard 61362 First Edition is made not less than the gain Kd before the rotational speed of the runner is adjusted to be synchronized with the frequency of the electric power transmission line, so that the derivative calculation element is made dominant in comparison with the integration calculation element. 
     
     
       5. A method according to  claim 1 , wherein a gain of at least one of the derivative calculation element and an integration calculation element before the rotational speed of the runner increases to the vicinity of a rated rotational speed and the gain of the at least one of the derivative calculation element and the integration calculation element after the rotational speed of the runner increases to the vicinity of a rated rotational speed are allowed to be different from each other, and the gain of the at least one of the derivative calculation element and the integration calculation element is set so that the derivative calculation element is made dominant in comparison with the integration calculation element before the rotational speed of the runner is synchronized with the frequency of the electric power transmission line after the rotational speed of the runner increases to the vicinity of the rated rotational speed. 
     
     
       6. A method according to  claim 1 , wherein after the rotational speed of the runner is synchronized with the frequency of the electric power transmission line and the electric power generator is connected in parallel to an electric power system, the governor increases the opemng area of the wicket gate to separate an operating point away from S-shaped characteristic curve portion. 
     
     
       7. A method according to  claim 1 , wherein after the rotational speed of the runner is synchronized with the frequency of the electric power transmission line and the electric power generator is connected in parallel to an electric power system, the derivative calculation element is prevented from being dominant in comparison with the other calculation element, and a gain of at least one of the derivative calculation element and an integration calculation element is set at a predetermined value for bearing a load. 
     
     
       8. A method according to  claim 1 , wherein a proportional gain Kp of the governor along IEC International Standard 61362 First Edition before the rotational speed increases to a rated value is more than 0.6, and the proportional gain Kp is less than 0.5 with that a derivative gain Kd along IEC International Standard 61362 First Edition is more than 5 before the rotational speed is synchronized with the frequency of the electric power transmission line after the rotational speed increases to the rated value. 
     
     
       9. A method for operating a pump turbine apparatus including a runner rotatable in either of a direction for driving an electric power generator and a direction for pumping a water, a main shaft for transmitting a rotation of the runner to the electric power generator, a wicket gate for adjusting a flow rate of water for driving the runner, and a governor for controlling an opening area of the wicket gate to change a rotational speed of the runner,
 wherein when Q is the flow rate of the water for rotationally driving the runner, H is a head of the water for rotationally driving the runner, N is an actual rotational speed of the runner, N 1 =N/√H, Q 1 =Q/√H, and the rotational speed of the runner is adjusted to be synchronized with the frequency of the electric power transmission line during rotational start of the runner in an electric power generating mode with ∂Q 1 /∂N 1 >0, gains of a derivative calculation element in a system for controlling the rotational speed of the runner and the other calculation element in the system are changed so that the derivative calculation element is dominant in comparison with the other calculation element in the system. 
 
     
     
       10. A method for operating a pump turbine apparatus including a runner rotatable in either of a direction for driving an electric power generator and a direction for pumping a water, a main shaft for transmitting a rotation of the runner to the electric power generator, a wicket gate for adjusting a flow rate of water for driving the runner, and a governor for controlling the wicket gate to change a rotational speed of the runner,
 wherein when Q is the flow rate of the water for rotationally driving the runner, H is a head of the water for rotationally driving the runner, N is an actual rotational speed of the runner, N 1 =N/√H, Q 1 =Q/√H, and the rotational speed of the runner is adjusted to be synchronized with the frequency of the electric power transmission line during rotational start of the runner in an electric power generating mode with ∂Q 1 /∂N 1 >0, a phase lag of at least one of a timing of transition from an increase of an opening area of the wicket gate to a decrease thereof with respect to a timing of transition from an increase of the rotational speed to a decrease of the rotational speed and a timing of transition from the decrease of the opening area of the wicket gate to the increase thereof with respect to the timing of transition from the decrease of the rotational speed to the increase of the rotational speed is not more than 120 degrees. 
 
     
     
       11. A method for operating a pump turbine apparatus including a runner rotatable in either of a direction for driving an electric power generator and a direction for pumping a water, a main shaft for transmitting a rotation of the runner to the electric power generator, a wicket gate for adjusting a flow rate of water for driving the runner, and a governor for controlling the wicket gate to change a rotational speed of the runner,
 wherein when Q is the flow rate of the water for rotationally driving the runner, H is a head of the water for rotationally driving the runner, N is an actual rotational speed of the runner, T is a torque for rotationally driving the runner, N 1 =N/√H, Q 1 =Q/√H , T 1 =T/H , and the rotational speed of the runner is adjusted to be synchronized with the frequency of the electric power transmission line during rotational start of the runner in an electric power generating mode with at least one of ∂Q 1 /∂N 1 >0 and ∂T 1 /∂N 1 >0, a derivative calculation element is dominant in comparison with the other calculation element to mainly control the rotational speed. 
 
     
     
       12. A method according to  claim 11 , wherein the governor along IEC International Standard 61362 First Edition has a proportional gain less than 0.5 and a derivative gain more than 5. 
     
     
       13. A method for operating a pump turbine apparatus including a runner rotatable in either of a direction for driving an electric power generator and a direction for pumping a water, a main shaft for transmitting a rotation of the runner to the electric power generator, a wicket gate for adjusting a flow rate of water for driving the runner, and a governor for controlling the wicket gate to change a rotational speed of the runner,
 wherein when Q is the flow rate of the water for rotationally driving the runner, H is a head of the water for rotationally driving the runner, N is an actual rotational speed of the runner, N 1 =N/√H, Q 1 =Q/√H, and the rotational speed of the runner is adjusted to be synchronized with the frequency of the electric power transmission line during rotational start of the runner in an electric power generating mode with ∂Q 1 /∂N 1 >0, the wicket valve is controlled mainly by a derivative calculation element of the governor to keep the rotational speed stable against a variation of the rotational speed, and the other calculation element operates for at least one of controlling the wicket valve to keep the rotational speed against another variation of the rotational speed whose cycle period in variation is significantly longer than that of the variation of the rotational speed against which the derivative calculation element controls the wicket valve, and controlling the wicket valve in a negligible degree.